Conventional passive lift devices, mounted to the torso of a person and configured to support the weight of the arm, are not able to automatically cut or substantially reduce assistance when the person intends to rest his/her upper arm at his/her side, or pick a tool from his/her tool belt. Such devices do not provide a sustained range of position where support torque automatically reduces to zero. Except for a few position points, these devices continuously apply lifting forces to a person's upper arm, potentially inhibiting motion and creating discomfort during non-working postures when assist is not desired.